Not sure this is the right section for this but seeing as its a fairly hefty, serious performance mod i thought it may be relevant and of interest to the more motorsport orientated, not to mention making for a good discussion. Right, i've been looking into carbon parts for a while now and whilst i understand the process for moulding and the theory of physically removing the roof, i am at a loss when it goes beyond this-especially with regard to rigidity, installation, protection and of course cost I've got quite a few questions but it could go on for an eternity so i'm interested to hear you thoughts/experiences on the subject. thanks
I'm currently investigating replacing the ffsr roofskin with a hardtop one. I ground out the last one and rivetted/siliconed an alloy plate over the hatch, but want it nice this time. Carbon would be nice but I'd imagine a part that size would be way too pricey. Anyone?
it is large but is it particularly complicated under the rain gutters and down the front of the a pillars? I've never looked. i think i'll do a bit of digging over the next few days and see what i can turn up.
if not pinned into the car i.e the a/b/c pillers and along the length of the car you will lose alot of strength in the shell . crap idea
with bonding it in it would have to have no voids . doweled in etc . you will lose so much rigidity in the shell . 100 times better off fitting poly windows and composite wings/boots etc . maybe for a show car but not a home grown go car. have you ever looked at minis or mk1 / mk2 golfs that get used on track ? take a look at the corners and side lengths of the roof skins and i will expect you will see slight dents in it . (thats stress marks) imagine what will happen if you bonded a skin on ? i wouls imagine you will be fitting new roofs ever other year .
i was wondering about that-obviously a huge potential pitfall though i'd imagine a good cage would compensate (albeit more than negating any weight savings made) Does anyone have any images of the all-smiles 'carbon car'? I seem to remember seeing a pic showing the wiper/scuttle area in carbon. Not seen nor heard of it in a long time though
I know a bloke that works at crosby composites, he's in charge of the quality controll area for the carbon fibre stuff. I wont see him untill about the 12th but I'll get his proffesional opinion on the topic and post it up. I got a feeling he'll say its not worth the bother though and as a side point if you dont have access to an autoclave big enough to "bake off" a roof skin then you'll end up with a really poor quality result.
Great advice guys thanx alot, i too have been trying to find out about the same thing, and im a newbie to the motorsport scene, i mite leave the old tin top as it is then lol and stick with getting polycarbonate windows, fibreglass bonnet, tailgate, and possibly wings. Any other tips on weightloss anyone? booked my first trackday ever for january cant wait!
Thanks chris, though i have had no luck getting on to it either. found this though The chap doing it has said if he'd know how involved it was he may not have started it. speaks volumes really and certainly relegates it to the really talented/experienced/connected of us. Thats me out for sure unless i can wangle a job at pagani or konigsegg etc........ i have to say gillm, i've never looked that closely at such things and haven't heard of it happening before-though i would hardly describe myself as experienced in these matters. The autoclave issue was one i thought of after posting but ultimately is one that i guess 'could' be worked around. (tape up wndows/doors and turn the heating up to 11??! ) skint-would definately be interested to hear what another pro has to say about this. all good stuff guys, keep em coming
rubbish, you really think a 1m square 1mm thick skin is going to add any rigidity? please....that's what the rollcage is for. If it was that bad they wouldn't do it on M3's, and they certainly wouldn't put sunroofs in cars either.... it's literally a skin, you leave all the surround and gutter and pillars in, [YOUTUBE]4vuDhs6YaYo[/YOUTUBE]
Fair do's, 'phat vr6' gotta point, makes sense. The rigidity is in the roof frame not the skin,plus a nice cage keep things nice and safe too. Anyone know who makes carbon or glass fibre roofskins?
a couple of things i've just stumbled upon http://www.i-club.com/forums/showthread.php?t=165524 http://www.streetunit.com/FI_CF_Roof_Skin_MS6_w_o_MR_p/fims6cfrs.htm on an evo of sorts seems more common than expected but from the little i've read so far, there seen to be conflicting views on its suitability and the effects. However, that porsche above is the real deal and apparently was simply bonded in as per the BMW M6 I know carbon can be made v. stiff so theoretically the panel itself should be able to match or even exceed the steel and from the pics above it appears the fitment isn't resevered for just the limited run oem specials. Anyone know what, if any, changes were made to the M3 csl's structure (E46) to accomodate the roof?
http://www.performance-trim.com/product.php?product_id=95&category_id=17 These guys do a lot of replacement carbon fibre parts.
jon-i'm not sure on the bonding side of things but there were bolts all the way round http://forums.evolutionm.net/automotosports-illinois/322055-ams-carbon-fiber-roof-being-installed.html
as Phat's says its just a skin, it does add some strength but very little, the main bulk of the strength is in the roof rails and also the box section of sorths that bridges between the 2 roof rails to make a ladder section, the roof skin will help tie it together but will not do too much. also if you are doing this to save wieght and lower the centre of gravity its a hell of a lot of work for a couple of kilos, you will lower the centre of gravity better by plastic windows and fiberglass bonnet and boot. mk1/2 cars get dimples on the roof as the whole body shell is not that ridgid compared to later cars (as can be seen by crash tests) so as the body flexes more it distors the roofskin, but a caged and braced car will help reduce the flex.
autoclave's use heat and pressure to cure resin parts. hence why they are so feckin expensive and rare! carbon roofskins on an old vw platform car are a waste of time unless you have a full weld in cage that ties all suspension points together and is also tabbed to the boyshell.
You don't have to use an autoclave though-for stressed parts sure, but a wet layup is adequate for other parts-the big question is 'just how stressed is the roof panel?' Even if we could prove its not a structural part 'as such', i'm sure that it must take 'some' of the forces as implied by the dimpling metioned earlier. But would a wet layed piece suffice on its own-i don't know enough to say either way. However, I think anyone doing it would probably be caging the car anyway so in that case you may be ok with a 'decorative' carbon skin the trouble is, whatever the reality of the roof skins role, all of the above links/pics are for more modern machinery and their panels don't go any further than the top of the windscreen whereas the mk1's and 2's continue around the screens making then far more complicated. I still love the idea personally, but its well beyond my means.
